JP-A-2004-297780 discloses an auto document feeder for a scanner having a separation roller that is rotated while contacting an uppermost one of documents stacked vertically and a separation pad arranged to oppose to the separation roller.
The auto document feeder (referred to as “ADF” hereinafter) suffers from the following problem: When the ADF is operated in a condition that a large number of documents are loaded (set), a leading ends of initial several sheets (in particular a first sheet) of the automatically fed documents are likely to be bent (this defect is referred to as a “leading end folding” hereinafter).
Incidentally, JP-A-8-319037 discloses a device for feeding a sheet at a slow speed before separation of the sheet from the stacked sheets and feeding the sheet at a high speed after the separation of the sheet from the stacked sheets, in order to separate the stacked sheets one by one surely and feed the sheet at a high speed. However, since this device is featured by changing a feeding speed for a sheet before and after the separation, it is difficult for this device to solve the leading end folding occurring in separating the stacked sheets.